I have about a 40 foot run of 3/4" pipe between my hot water heater and just about every fixture in the house, which, when combined with today's low-flow fixtures, means a full minute wait for hot water. I am intrigued by the idea of a gravity fed recirc loop-- nearly instant hot water for $100 in parts and a Saturday afternoon, all powered by the laws of physics! (And it will force me to finally get around to flushing the HWH)
I'm curious though-- those of you who have installed one, how has it affected your utility costs? It seems like it might be noticeably more expensive to keep the pipes hot 24/7.
Another option I'd considered is 1/2" pex home runs for the hot water for the two bathrooms and kitchen-- by reducing the diameter of the pipe from 3/4" copper to 1/2" pex, I'd be reducing the amount of cold water to be purged by about 40%, so hot water 40% faster. At least with this option, I'm not heating the pipes constantly. Is there any downside to this option?
I'm curious though-- those of you who have installed one, how has it affected your utility costs? It seems like it might be noticeably more expensive to keep the pipes hot 24/7.
Another option I'd considered is 1/2" pex home runs for the hot water for the two bathrooms and kitchen-- by reducing the diameter of the pipe from 3/4" copper to 1/2" pex, I'd be reducing the amount of cold water to be purged by about 40%, so hot water 40% faster. At least with this option, I'm not heating the pipes constantly. Is there any downside to this option?